People who used both tobacco and cannabis products were more likely to screen positive for depression than users of either alone

Co-use of tobacco and cannabis was associated with higher odds of depression screening positive compared to tobacco-only (aOR 1.32) and cannabis-only (aOR 1.94) use. Among specific products, e-cigarette use (aOR 1.56), cigarette use (aOR 1.24), and chewing tobacco (aOR 1.91) were individually associated with depression. The most common two-product combination among depression-positive individuals was nicotine e-cigarettes and smoked cannabis (27.6%).

Cross-sectional online survey of a national convenience sample of 6,038 people aged 13-40. Depression screening and past 30-day use of 11 specific tobacco and cannabis products assessed. Analyses stratified by age group.

By examining specific product combinations, this study reveals that the e-cigarette plus smoked cannabis pairing is the dominant pattern among depressed co-users, providing a concrete target for screening and intervention efforts.

The specific product-level analysis suggests that the mode of consumption matters. E-cigarettes and smoked cannabis share an inhalation delivery method that may create compound respiratory and neurochemical effects beyond what either product alone produces.

Cross-sectional design cannot determine if co-use causes depression or depressed individuals gravitate toward co-use. Convenience sample. Self-reported product use and depression screening (not clinical diagnosis). Cannot control for all confounders.